Air Installations Compatible Use Zone

Noise Zones and Noise Metrics

Under the AICUZ Program, the Department of Defense (DoD) provides noise zones as a planning tool for local agencies. Noise exposure is measured using the Community Noise Equivalent Level (CNEL). The CNEL metric is based on the number of annual average daily aircraft operations over a 24-hour period. CNEL includes a 10 decibel (dB) adjustment, or penalty, for aircraft noise occurring during the nighttime (10 p.m. to 7:00 a.m.) and a 5 dB adjustment for events during the evening (7 p.m. to 10 p.m.) because people are more sensitive to noise during these periods. CNEL has become the standard metric used by many government agencies and organizations and is prescribed by the State of California for addressing aircraft noise. The map to the right displays the relevant CNEL contours.

Accident Potential Zones

The DoD provides Accident Potential Zones (APZs) as another planning tool for local agencies. The APZ concept describes the areas of highest probability for aircraft impact if a mishap were to occur. Aircraft operations are not limited to areas with APZs and can potentially be routed anywhere within the Class B airspace established around MCAS Miramar. The size and shape of current APZs are depicted in the map to the right.

• Clear zones (CZs) are defined as the area immediately beyond the usual runway threshold. They are areas with the greatest potential for the occurrence of aircraft accidents. CZs should remain undeveloped.

• APZ-I is defined as the area immediately beyond the CZ that still possesses a measurable potential for aircraft accidents relative to the CZ. The APZ-I is identified under flight tracks that experience 5,000 or more annual fixed-wing operations (departures or approaches, but not both combined).

• APZ-II is defined as the area immediately beyond APZ-I (or CZ if APZ-I is not designated) which has a measurable potential for aircraft accidents relative to APZ-I or the CZ. APZ-II is designated whenever APZ-I is required.

What has been done

MCAS Miramar has minimized its operational impacts to the community to the greatest extent practical while maintaining safe operations and meeting mission and training requirements. MCAS Miramar has also cooperated with the San Diego Regional Airport Authority and City of San Diego to implement the Airport Land Use Compatibility Plan for MCAS Miramar, which was adopted in 2008 and amended in 2011. Fortunately, the adopted Airport Land Use Compatibility Plan has incorporated compatibility standards consistent with AICUZ 2005. These have proven generally effective at preventing incompatible development and remain consistent with the 2020 AICUZ recommendations.

What are the benefits

In addition to protecting the public health and safety, other benefits provided by MCAS Miramar include protecting the taxpayer’s investment in national defense assets and protecting economic benefits to the surrounding communities. The local economy is enhanced by MCAS Miramar’s expenditures for salaries, contracts, construction, retirement pay, tuition aid to schools, health insurance payments, and off installation accommodations for travelers. In terms of total economic impact in the region, MCAS Miramar has had an estimated annual total economic impact of nearly $650 million resulting from payroll expenditures, annual expenses, and the estimated value of indirect jobs in the local area. Land Use Compatibility Guidelines

In general, the Navy and USMC land use compatibility guidelines, as outlined in OPNAVINST 11010.36C/ MCO 11010.16, recommend that noise sensitive land uses be placed outside high-noise zones and people-intensive uses not be placed in APZs. Certain land uses are considered incompatible with high noise zones and APZs, while other land uses may be considered compatible or compatible under certain conditions (compatible with restrictions). Land use development should be compatible with noise zones and APZs around a military airfield. Although the military can serve in an advisory capacity, local governments control the development beyond the boundaries of MCAS Miramar. The AICUZ footprint of an air station – comprised of noise contours and APZs - defines the minimum acceptable area in which land use control measures are recommended in order to prevent development that is incompatible with airfield operations.

Sound Insulation

Construction of new buildings or additions to existing structures must comply with California State building code. The AICUZ Program, as specified in MCO 11010.16, includes noise attenuation recommendations. Local governments adoptions of these sound attenuation guidelines minimizes noise impacts on building inhabitants.